Mrs Rausing, one of Britain's richest women, was found dead in a bedroom of the opulent Cadogan Place house in London's Chelsea which she shared with Mr Rausing.

The inquest into Mrs Rausing's death heard from Detective Inspector Sharon Marman, who told coroner Dr Shirley Radcliffe that Mr Rausing, 49, was stopped on suspicion of driving under the influence of alcohol or drugs on July 9.

Officers found drugs in his car and when they searched the couple's home they discovered Mrs Rausing's body.

Mr Rausing was arrested but is currently under medical supervision and detectives have been unable to interview him. He was represented at the inquest opening at Westminster Coroner's Court by Neil Saunders QC, who represented 10 families at the inquest into the 7/7 bombings.

A post-mortem examination proved inconclusive and further test results are awaited, the officer added. There was no comment on how long Mrs Rausing's body had lain in the five-storey Georgian townhouse. According to reports it may have been there for several days.

It is thought a decision will made next week about when the mother-of-four's body will be released. One post-mortem examination has been carried out by a pathologist, with a second pathologist for Mr Rausing present. The parties will return to the court on October 5 for a hearing in private to review the case.

The couple's drug problems have been widely reported. In 2008 they were investigated by police over drugs but the prosecution was formally discontinued.

Mr Rausing, heir to a £5.4 billion fortune from his Swedish father's business, was charged with drugs offences after police found crack cocaine, cocaine and heroin during a search of his home. After lengthy discussions between his legal team and prosecutors, he accepted a conditional police caution instead.